Spacer bar and key locking mechanism for typewriters and similar machines

ABSTRACT

A key locking mechanism and spacer bar locking mechanism for typewriters and similar machines adapted to prevent the full depression of the typing keys and spacer bar when the carriage of the typewriter has reached a predetermined position during a typing sequence. The locking mechanism comprises a locking bar having a main stop surface and an auxiliary stop surface which is mounted slightly below the main stop surface and which is positioned in front of the main stop surface in the direction to the pivoting movement of the locking bar. A two-armed disconnecting lever is pivotally supported on the typewriter frame. One arm of the two-armed lever is connected by means of a rod to the locking bar. The other arm of the locking lever extends into the path of movement of the typewriter carriage. When the latter has reached a predetermined point in its travel it causes a pivoting of the two-armed lever thereby causing the locking bar and locking stop post to move into their locking positions and thereby prevent the depression of the typewriter keys or spacer bar.

United States Patent [72] lnventors Miroslav Blaha;

Rostlslav Slama; Jan Sobotka; Frantisek Hemzal, all of Brno, Czechoslovakla [21] Appl. No. 783.900 [22] Filed Dec. 16, 1968 [45] Patented Nov. 9, 1971 [73] Assignee Zbrojovka Brno, narodini podnik Brno, Czechoslovakia [32] Priority Dec. 15, 1967 3 3 Czechoslovakia [31] 8865/67 [54] SPACER BAR AND KEY LOCKING MECHANISM FOR TYPEWRITERS AND SIMILAR MACHINES 5 Claims, 6 Drawing Figs. [52] US. Cl 197/107, 1971110 [51] Int. Cl .i B41j 5/22, B41 j 29/56 [50] Field of Search 197/108, 110, 107, 193,98

[56] References Cited UNITED STATES PATENTS 764,070 7/1904 Parker 197/110 1,137,417 4/1915 Nathan 197/110 1,215,586 2/1917 Smathers... 197/110 1,841,111 1/1932 Garbell 197/110 1,864,540 6/1932 Helmond 197/1 10 Primary Examiner-Robert E. Pulfrey Assislam Examiner-Stephen C. Pellegrino Attorney-Arthur O. Klein ABSTRACT: A key locking mechanism and spacer bar locking mechanism for typewriters and similar machines adapted to prevent the full depression of the typing keys and spacer bar when the carriage of the typewriter has reached a predetermined position during a typing sequence. The locking mechanism comprises a locking bar having a main stop surface and an auxiliary stop surface which is mounted slightly below the main stop surface and which is positioned in front of the main stop surface in the direction to the pivoting movement of the locking bar. A two-armed disconnecting lever is pivotally supported on the typewriter frame. One arm of the two-armed lever is connected by means of a rod to the locking bar. The other arm of the locking lever extends into the path of movement of the typewriter carriage. When the latter has reached a predetermined point in its travel it causes a pivoting of the two-armed lever thereby causing the locking bar and locking stop post to move into their locking positions and thereby prevent the depression of the typewriter keys or spacer bar.

PATENTEU U 9 I97l 3, 6 1 8 7 3 7 SHEET 1 OF 3 INVENTOR Hiroscav BLA HA, Rad w ov SLANA "ATTORNEY SPACER BAR AND KEY LOCKING MECHANISM FOR TYPEWRITERS AND SIMILAR MACHINES BACKGROUND OF THE INVENTION The present invention relates to a key and spacer bar locking mechanism for typewriters, accounting machines, and the like.

In particular, the present invention relates to a mechanism of this type which is adapted to prevent the full depression of the typewriter keys and spacer bar when the carriage of the machine has reached a predetermined position.

Locking mechanisms for the typewriter keys and the spacer bar of a typewriter are of course known in the art. These known mechanisms generally are moved into their operative locking position by means of a terminal stop movably mounted in the frame of the typewriter. This terminal stop actuates a system of levers and rods which either move a stop into an operative position in which it prevents the mechanism of the release device from being actuated or a deflectable locking bar is moved into the paths of all key levers so as to prevent them from being depressed. The first one of the above-described two alternate known embodiments has an important drawback in that the already locked key levers and spacer bar are subjected to relatively large bending stresses when being hit by the fingers of a typist. The delicate mechanisms of the release means of the carriage are similarly subjected to excessively large stresses. The second of the above-described two alternate known embodiments has another important drawback, in that'it locks only the key levers so that the spacer bar must again be locked by the stopping of the release means of the typewriter mechanism thereby again subjecting the relatively long arms of the spacer bar to excessively large stresses.

There often occurs during the course of a rapid typing operation the involuntary typing of a type. This sometimes occurs because the key levers of the typewriter need a minimum amount of time to return to their initial inactive position from their typing position. Similarly it takes a minimum amount of time for the locking bar to reach its locking position. Because of these time lags it is possible that the locking bar moving to its locking position encounters the front edge of the stop nose of a returning key lever, thereby preventing the locking bar from moving into a full locking position. If, at the aforedescribed moment of encounter another key is depressed, the latter can freely move to its typing position without being stopped in such movement by the locking bar. In order to eliminate this drawback it has been proposed to provide the key levers with an additional stop nose which is designed to impinge on the locking bar in case the first stop nose of the key lever slips by the locking bar. This solution presents the drawback of requiring a complete replacement of the key levers in the existing typewriters with the new key levers having two stop noses if the aforedescribed drawback is to be eliminated from these existing typewriters. Even when the existing typewriters have been so modified, the locking of the spacer bar is again carried out either by the stopping ac tion of the operating mechanism of the release means or there is no spacer locking device provided at all in the typewriter. In the latter case, if the spacer bar is pressed down after the keys have been locked, the carriage will move one more step, which requires the typist, when adding a type or hyphen to return the carriage by one step.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a construction which will avoid the above described drawbacks.

It is a more specific object of the present invention to provide a reliable mechanism for locking the key levers and spacer bar of typewriters and similar machines, which has an extremely simple and compact construction.

Also, it is an object of the invention to provide a locking mechanism which operates satisfactorily without applying excessive bending stresses to the arms of the typing keys or the spacer bar.

It is a further object of this invention to provide a locking mechanism which can be easily adapted to existing typewriters.

It is still another object of this invention to provide a locking bar in a locking mechanism which can be constructed so as to have an increased bending strength.

In accordance with the invention, the frame of the typewriter carries a locking bar which has a main stop surface at an upper level and an auxiliary stop surface at a lower level, said auxiliary surface being located in front of the main surface in the direction of the pivoting movement of the locking bar. The latter is connected by means of at least one rod to a locking stop post slidably mounted in the frame of the typewriter immediately underneath the spacer bar.

The locking stop post may also be fitted with an auxiliary stop surface located at a lower level than the main stop surface thereof and in front of the latter in the direction of displacement of the locking stop post into its locking position. The locking bar is supported by auxiliary means in order to avoid an excessive deflection due to bending.

BRIEF DESCRIPTION OF DRAWING The invention is illustrated by way of example in the accompanying drawing which forms part of this application and in which: 7

FIG. 1 is a schematic elevational view of the locking mechanism of this invention;

FIG. 2 is a plan view of the mechanism illustrated in FIG. 1;

FIG. 3 is a schematic fragmentary view in perspective of a second embodiment of a locking bar of the locking mechanism in accordance with this invention the central portion of the locking bar being omitted;

FIG. 4 is a partial schematic view in perspective of the second embodiment of the locking bar of a locking mechanism in accordance with this invention;

FIG. 5 is a schematic illustration in perspective of a third embodiment of a locking bar of a locking mechanism in accordance with this invention; and

FIG. 6 is an elevational schematic view illustrating the locking bar in its locking position and a key lever in a locked position.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawing, there is illustrated in FIGS. 1 and 2 a locking bar 4 having a pair of suspension arms 3 respectively mounted in triangular apertures l disposed in operative sidewalls 2 of the frame 33 of a typewriter or a similar machine. The locking mechanism of this invention may be used in conjunction with any standard typewriter having the usual movable carriage mounted therein. The typewriter mechanism and carriage are, therefore, not illustrated in detail because these components are well known in the art and their illustration would obscure the subject matter of this invention. The locking bar 4 extends below the key levers 19 across the entire width of the typewriter. As can be noted from FIG. 1, the locking bar 4 may be L-shaped and has an upper surface 5 which constitutes the main stop surface. An angle-shaped member 6 is secured to the locking bar 4 along the sidewall 15 thereof, as illustrated in FIG. 1, by welding or other suitable means. This angle-shaped member 6 has an upper leg, the upper surface of which constitutes an auxiliary stop surface 7. As can be noted from FIG. 1, the auxiliary stop surface 7 is located below the main stop surface 5 and also in front of the latter with respect to the direction of movement of the locking bar towards the stop noses 24 of the key levers 19. The pivoting movement of the locking bar 4 towards the stop noses 24 is indicated by an arrow in FIG. 1. The stop surface 7 is arranged and located so that, when one of the stop noses 24 bears against it, the corresponding type will be prevented from typing and from tripping the (nonillustrated) carriage release mechanism. A spring 8 connects the locking bar 4 to the sidewall 2 of the machine frame 33, as illustrated in FIG. 2. The spring 8 maintains the locking bar 4 in its inoperative position. There is furthermore provided a two-armed disconnecting lever 11 which is pivotally mounted on the frame 33 of the typewriter by means of a pivot shaft 12. The carriage (not illustrated) of the typewriter has a stop bar 14 which is engaged by the arm 13 of the two-armed lever 11 when the carriage has reached a predetermined point in the typewriter, which causes the carriage to stop. The other arm of the two-armed lever 11 bears against a stop 38 which thereby determines the inoperative position of the locking bar 4. As can be noted from FIG. 2, the locking bar 4 has a projecting tooth 16 which is adapted to extend through an opening 17 of a guide comb 18 extending between opposite sidewalls 2 of the typewriter frame 33. The projecting tooth 16 is engaged by the guide comb 18, which thereby aids in supporting the locking bar 4 when the latter has moved into its locking position. As can be noted from FIG. 4, the guide comb 18 has a plurality of cutouts 35 which serve for guiding the key levers. 19. The latter are pivotally mounted in the typewriter on a shaft 20 which is supported in the frame 33. Each key lever 19 is also connected to the frame 33 by means of a spring 22 which urges each key lever 19 against a fixed stop 21. A rod 23 is pivotally connected to each key lever 19 on the one hand and is pivotally connected to the type bar (not illustrated) on the other hand. Each key lever 19 is furthermore provided with a stop nose 24 which has a front face 40, the latter just passing the main stop surface 5 and the auxiliary stop surface 7 when the key lever 19 is pivoted in the direction of the arrow in FIG. 1 during a typing operation when the locking bar 4 is in its inoperative position. The locking bar 4 has at its midsection an opening 25 to which the hook ofa rod 26 extends, the other end of the rod 26 being connected to a stop plate 27. This stop plate 27 is arranged underneath the space bar 28 and is supported on the spacer stop plates 29 which are fixedly secured to the frame 33 of the typewriter. The two opposite ends of the stop plate 27 carry a pair of stop posts 31 normally extending therefrom into a recess 34 disposed in the undersurface of the spacer bar 28. The latter is secured to a pair of arms 32 which are operatively connected to the release mechanism of the carriage (not illustrated). The middle one of the spacer stop plates 29 has an elongated guiding aperture 36, the longitudinal axis of which is substantially perpendicular to the longitudinal axis of the spacer bar 28. The stop plate 27 has a downwardly extending projection 37 which extends into the elongated aperture 36. The aperture 36 is adapted to guide the projection 37 and thereby guide the stop plate 27 in its reciprocal movement. The stop plate moves simultaneously with the locking bar 4, as they are connected by the connecting rod 26, as above-explained. The stop plate 27 is firmly connected with the connecting rod 26, which is fixed with its other end in the opening 25. A projection 37 is provided on the stop plate 27, engaging into an elongated aperture 36. This prevents any turning of the stop plate 27 around the projection 37. The stop posts 31 must be distant from the recesses 34. When the spacer bar 28 is closed, the stop posts 31 are shifted below the lower edge 41 of the spacer bar 28 and prevent its pressing down.

As may be noted from FIGS. 3 and 4, the locking bar here designated 4 may have an S-shaped profile. Them main stop surface 5, the pair of suspension arms 3 and auxiliary stop surface 7, together with a second embodiment of the locking bar 4' are best illustrated in FIG. 3.

A second alternate embodiment of the locking bar 4' as well as the guide comb 18 are illustrated in FIG. 4. The guide comb 18 has a pair of projections 39 which aid in supporting the locking bar 4 when it has been moved to its locking position.

A third alternate embodiment of a locking bar 4" is illustrated in FIGS. 5 and 6, which has a main stop surface 5" and an auxiliary stop surface 7" similarly shaped and arranged as in the locking bar 4 illustrated in FIG. 1. The suspension arms 31" of the embodiment of FIGS. 5 and 6 extend, however, downwardly. The arrow indicates the direction of the pivoting movement as the locking bar 4" moves to its locking position.

A single auxiliary stop surface 7 has been found in practice to suffice for adequately stopping the key levers 19 and spacer bar 28. It is of course, also possible to provide additional auxiliary stop surfaces between the main stop surface 5 and the auxiliary stop surface 7. What is essential to the invention is that when the locking bar 4 is in impossible. locking position, the main stop surface 5 determines the minimum stroke of the key lever 19 when locked, and the auxiliary stop surface 7 determines the maximum stroke of the key lever 19 when locked, whereby no printing of a type can occur and the tripping of the release mechanism of the typewriter cannot be effected. If the locking bar is in the locking position, the main stop surface 5 bars the advance of the stop noses 24 of all key levers l9 and their movement from the main stop surface 5 to the auxiliary stop surface 7 is impossible The opposite movement is possible, as described hereinafter.

It is also possible to modify the arms 32 of the spacer bar 28 and the stop noses 24 of the key levers 19 in such a way that the locking bar 4 itself acts as a lock of the spacer bar 28. It is also possible to form similar auxiliary stop surfaces on the stop locking posts 31 of the stop plate 27 of the spacer bar 28.

When the terminal stop bar 14 hits the arm 13 of the twoarmed disconnecting lever 11, the arm 10 is pivoted away from the front of the typewriter and causes the rod 9 to pull the locking bar 4 towards the rear of the typewriter, thereby pivoting the latter about its support formed by the engagement of the suspension arms 3 with sidewalls 2 in the apertures 1, and thereby moving the locking bar 4 into the locking position, as indicated by the arrow in FIG. 1. When one of the key levers 19 is now manually depressed, its stop nose 24 impinges on the main stop surface 5 of the locking bar 4. The depression of the key lever 19 is thus limited to such an extent that its downward movement is insufficient to fully activate either the type lever 23 or the release mechanism for the carriage of the machine. When a rapid typing operation is in progress, it is possible that a depressed key lever 19, during its return motion, has covered only approximately half the distance at the point when the movement of the locking bar 4 toward its locking position begins. In such a case, the locking bar 4 engages the front face of the stop nose 24 of the key lever 19, as illustrated in FIG. 6. If, at this moment, another key lever 19 is manually depressed, its stop nose 24 will fail to touch the main stop surface 5 of the locking bar 4, but will impinge on the auxiliary stop surface 7 which still limits the downward movement of the key lever 19 sufficiently. The earlier actuated key lever 19 returns in the meantime into its starting position by the action of spring 22. After release of pressure on another key lever 19, it returns equally due to the action of spring 22 into its starting position, whereafter the locking bar 4 finishes the turning into the locking position and the main stop surface 5 bars the track for stop noses 24 of all key levers 19. Thus, even in this unusual case, the depression of the key lever 19 is sufficiently limited to prevent the operation of the type bar (not illustrated) and the release mechanism for the carriage of the machine. The stop plate 27 moves jointly with the locking bar 4, due to the action of the connecting rod 26, into its locking position, that is, the stop locking posts 31 are shifted below the lower edge 41 of the spacer bar 28 along the spacer stop plates 29 of the spacer bar 28 in which the stop locking posts 31 prevent the downward movement of the spacer bar 28.

Two alternate ways have been provided to prevent an excessive deflection and excessive bending stresses in the relatively long locking bar 4. As can be noted from FIG. 2, the locking bar 4 has a projection 16 at its midsection which extends into an aperture 17 of the guide comb when the locking bar 4 moves into its locking position. The guide comb 18 has a larger section modulus than the locking bar 4 and is rigidly mounted in the frame 33 parallel to the locking bar 4. Alternately, the guide comb 18 may have a plurality of projections 39 (see FIG. 4) which aid in supporting the locking bar 4. The required number of projections 39 depends on the length and strength of the locking bar 40'. It is possible to use the projection 16 together with the projections 39 as auxiliary supporting means.

Although our invention has been illustrated and described with reference to the preferred embodiments thereof, we wish to have it understood that it is in no way limited to the details of such embodiments but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed our invention, what we claim is:

1. In a typewriter and the like having typing keys and comprising a main frame having a reciprocably movable carriage mounted thereon, a spacer bar and key-locking mechanism for preventing the full depression of the typing keys and spacer bar when the carriage has reached a predetermined point in said typewriter, comprising in combination a plurality of key levers pivotally supported by said main frame, each key lever having a stop nose, a locking bar extending substantially across the entire width of said typewriter and being pivotally supported in opposite sides of said main frame for oscillating movement between an inoperative position and a locking position, means constantly urging the locking bar towards its inoperative position, disconnecting means operatively mounted on said main frame for engagement by said carriage when it has reached a predetermined point in its travel in said typewriter, said disconnecting means being operatively connected to said locking bar so as to move said locking bar between its inoperative position and said locking position in accordance with the movement of said carriage, said locking bar having a main stop surface and at least one auxiliary stop surface, the auxiliary stop surface being disposed below the main stop surface in the direction of movement of the stop nose of a key lever during its depression, said locking bar, when in its locking position, engaging the stop nose of a key lever with said main stop surface or said auxiliary stop surface when the key lever has been manually depressed by a typist and thereby preventing said key lever from operating.

2. In a typewriter and the like, the spacer bar and keylocking mechanism as set forth in claim 1, wherein said disconnecting means comprises a two-armed lever pivotally mounted on said main frame, a first arm of said two-armed lever being engaged by said carriage when it has reached said predetermined point and is pivoted thereby, a second arm of said two-armed lever being operatively connected to said locking bar and actuating the said locking bar in accordance with the pivoting movement of said two-armed lever.

3. In a typewriter and the like, the spacer bar and keylocking mechanism as set forth in claim 1, including a spacer bar operatively mounted on said main frame and being operatively connected to said carriage, locking stop means reciprocally mounted in said main frame underneath said spacer bar and being moved from an inoperative position to a locking position jointly with said locking bar, and at least one rod connected to said locking bar and said locking stop means to ensure their joint reciprocal movement in said main frame.

4. In a typewriter and the like, the spacer bar and keylocking mechanism as set forth in claim 3, wherein said locking stop means comprises a support plate reciprocally mounted underneath said spacer bar, and at least one locking stop post rigidly mounted thereon and normally extending therefrom toward said spacer bar, said locking stop post also having a second main stop surface and at least one second auxiliary stop surface which engage said spacer bar, said second auxiliary stop surface is disposed below said second mainstop surface and in front of said second main stop surface with respect to the direction of movement of said locking stop means from said inoperative position to said locking position.

5. In a typewriter and the like, the spacer bar and keylocking mechanism as set forth in claim 2, including auxiliary support means mounted in said main frame for aiding in the support of said locking bar when it is disposed in said locking position.

t t i i 

1. In a typewriter and the like having typing keys and comprising a main frame having a reciprocably movable carriage mounted thereon, a spacer bar and key-locking mechanism for preventing the full depression of the typing keys and spacer bar when the carriage has reached a predetermined point in said typewriter, comprising in combination a plurality of key levers pivotally supported by said main frame, each key lever having a stop nose, a locking bar extending substantially across the entire width of said typewriter and being pivotally supported in opposite sides of said main frame for oscillating movement between an inoperative position and a locking position, means constantly urging the locking bar towards its inoperativE position, disconnecting means operatively mounted on said main frame for engagement by said carriage when it has reached a predetermined point in its travel in said typewriter, said disconnecting means being operatively connected to said locking bar so as to move said locking bar between its inoperative position and said locking position in accordance with the movement of said carriage, said locking bar having a main stop surface and at least one auxiliary stop surface, the auxiliary stop surface being disposed below the main stop surface in the direction of movement of the stop nose of a key lever during its depression, said locking bar, when in its locking position, engaging the stop nose of a key lever with said main stop surface or said auxiliary stop surface when the key lever has been manually depressed by a typist and thereby preventing said key lever from operating.
 2. In a typewriter and the like, the spacer bar and key-locking mechanism as set forth in claim 1, wherein said disconnecting means comprises a two-armed lever pivotally mounted on said main frame, a first arm of said two-armed lever being engaged by said carriage when it has reached said predetermined point and is pivoted thereby, a second arm of said two-armed lever being operatively connected to said locking bar and actuating the said locking bar in accordance with the pivoting movement of said two-armed lever.
 3. In a typewriter and the like, the spacer bar and key-locking mechanism as set forth in claim 1, including a spacer bar operatively mounted on said main frame and being operatively connected to said carriage, locking stop means reciprocally mounted in said main frame underneath said spacer bar and being moved from an inoperative position to a locking position jointly with said locking bar, and at least one rod connected to said locking bar and said locking stop means to ensure their joint reciprocal movement in said main frame.
 4. In a typewriter and the like, the spacer bar and key-locking mechanism as set forth in claim 3, wherein said locking stop means comprises a support plate reciprocally mounted underneath said spacer bar, and at least one locking stop post rigidly mounted thereon and normally extending therefrom toward said spacer bar, said locking stop post also having a second main stop surface and at least one second auxiliary stop surface which engage said spacer bar, said second auxiliary stop surface is disposed below said second main stop surface and in front of said second main stop surface with respect to the direction of movement of said locking stop means from said inoperative position to said locking position.
 5. In a typewriter and the like, the spacer bar and key-locking mechanism as set forth in claim 2, including auxiliary support means mounted in said main frame for aiding in the support of said locking bar when it is disposed in said locking position. 